Morphological and molecular data reveal the cryptic diversity among populations of Aegla paulensis (Decapoda, Anomura, Aeglidae), with descriptions of four new species and comments on dispersal routes and conservation status.

The taxonomy of the Brazilian aeglid species Aegla paulensis Schmitt, 1942 from two disjunct hydrographic basins is revised using morphological and molecular data. Results show that six disjunctive populations of Aegla paulensis form a species complex. Aegla paulensis sensu stricto is redescribed and Aegla rosanae Campos Jr., 1998 is revalidated. The four remaining populations previously assigned to Aegla paulensis are now recognized as different species, namely Aegla  vanini n. sp., Aegla japi n. sp., Aegla jaragua n. sp. and Aegla jundiai n. sp. All new species are described and illustrated and are well supported by both morphological and molecular data. Aegla lancinhas Bond-Buckup & Buckup in Santos et al., 2015, which until recently was confounded with Aegla paulensis s. str., is supported as a valid species. A key to all members of the A. paulensis species complex is provided, and their phylogenetic and biogeographic relationships to other closely related species is discussed.

Description of the newly-hatched juvenile of Aegla perobae (Crustacea: Decapoda: Aeglidae).

The present paper contains the complete description of the external morphology of the first juvenile stage of Aegla perobae analysed through light microscopy (LM) and scanning electron microscopy (SEM). Newly-hatched juveniles were obtained from ovigerous females kept under laboratory conditions. Hatching is asynchronous, taking 2-4 days for all juveniles of a single brood to hatch. Average carapace dimensions are 1.54 mm wide and 1.69 mm long (rostrum excluded). Morphology of the carapace, of the cephalothoracic appendages (antennule, antenna, mandible, maxillule, maxilla, maxillipeds, and pereopods), of the pleon, and of the tail fan (telson plus uropods) are described in detail. Aegla perobae juveniles can be readily differentiate from the first juveniles of other aeglids species described so far by the upwardly curved condition of the distal region of the rostrum and the distinct groove along the orbital sinus produced the elevated free in this area. Pleopods 2-5 are present as rudimentary digitiform buds. Rudimentary pleopods are still present in adult males of the species, a trait not yet described in freshwater aeglids. This curious condition is compared and discussed in the light of the current knowledge of early postembryonic developmental patterns found in other anomurans.

Description of the newly-hatched juvenile of Aegla paulensis (Decapoda, Anomura, Aeglidae).

The postembryonic development of Aegla paulensis is epimorphic (= direct), in which the hatching form is a juvenile that morphologically resembles the adult. Hatching is asynchronous, taking 3-5 days for all juveniles from a single brood to hatch. This paper provides a complete description of the external morphology of the newly-hatched juvenile of A. paulensis as analyzed through light microscopy (LM) and scanning electron microscopy (SEM). One of the striking features ob- served in the newly-hatched juvenile of A. paulensis was the presence of four pairs of rudimentary pleopods, a trait never described before in early juveniles of Aegla. Additional novelties include three unique types of setae and two types of pore sensilla.